The present invention relates to a wear-resistant wrought Al alloy and it's production, and a scroll of the wear-resistant wrought Al alloy formed by forging and it's production.
More particularly, it relates to a wear-resistant wrought Al alloy which is used for a compressor for air-conditioner and automotive parts (e.g. piston, valve lifter or rocker arm for an engine) and it's production, that is, an Al alloy which has excellent fatigue strength at high temperature, high toughness and high flexure strength, in addition to high strength and high wear resistance required for materials, and it's production.
Extruded Al--Si (4032) alloy (Al-12 wt % Si-1.0 wt % Mg-1.0 wt % Ni alloy), ASTM 336.0 casting alloy (Al-12 wt % Si-1.0 wt % Mg-1.0 wt % Cu-1.0 wt % Cu alloy), ASTM 383.0 die-cast alloy (Al-11 wt % Si-2.5 wt % Cu alloy), etc. have hitherto been used for automotive parts, electric appliances, mechanical parts, etc., for which high strength and high wear resistance are required.
There has recently been increasing a case of using those obtained by (hot or cold) forging extruded materials or casting bar materials of aluminum alloys for these parts so as to make dimensional accuracy and strength high and to perform weight-saving.
On the other hand, with the increase of a demand for aluminum alloys, a required quality has been changing and becoming higher. For example, an improvement of high strength and high wear resistance as well as toughness and fatigue strength at high temperature is required for parts (e.g. scroll, wabble plate, etc.) used for a compressor for an air-conditioner.
Similarly, high strength and high wear resistance under a high-temperature environment (100 to 200.degree. C.) are required for automotive parts of the engine part (e.g. piston, valve lifter, rocker arm, etc.) and materials whose fatigue strength and toughness at high temperature are high are required.
However, in a conventional extruded aluminum alloy or aluminum casting alloy bar having the above composition, there has never been obtained a material having high fatigue strength and high toughness at high temperature in addition to high strength and high wear resistance.
An Al alloy extruded material obtained by adding a small amount of Fe, Mn, Cr, Sr and Ti to an Al-6-15 wt % Si--Cu--Mg--Ni alloy has been suggested for this application (e.g. Japanese Patent Application Laid-Open No. 7-197164/1995), however, it has not various characteristics and has a problem that high-temperature fatigue strength and toughness are inferior.
Furthermore, the form of the part as these sliding members has been complicated and a flexure strength represented by a compressor scroll has been required in addition to the above characteristics. Heretofore, a material which is superior in high-temperature fatigue strength, toughness and flexure strength has never been present.